Refugee children and families who are resettled in the United States face dramatic disparities in the incidence and treatment of mental health disorders. Resettlement stressors (poverty, limited access to care) and acculturative challenges (differences in cultural norms, discrimination) often exacerbate risks due to war- related trauma exposure. Commonly, refugee mental health services are limited-usually with a narrow focus on clinical treatment of PTSD-and rarely respond holistically to the needs or priorities of refugee communities; few interventions are designed for use across diverse cultures and refugee groups, despite rapidly evolving refugee demographics. Consequently, mental health service usage is low in resettled refugee populations. For refugee children and adolescents characterized by risk factors such as parental trauma, intergenerational conflict and other acculturative and resettlement stressors, preventive interventions hold great promise but are exceedingly rare. Cross-cultural application of community-based participatory research (CBPR) methods can increase understanding of risk and protective factors in refugee communities and contribute to development of responsive, flexible, interventions to promote healthy family functioning and child mental health and help prevent mental health disparities. We propose a CBPR-driven hybrid implementation effectiveness trial that builds upon ongoing collaborative research and community awareness-raising within Somali Bantu and Lhotshampas Bhutanese refugee communities in New England. Preliminary research and CBPR-based needs assessments with these groups has identified numerous cultural and community strengths as well as ongoing problems of difficult parent-child interactions, poor communication, and family conflict which interact with ongoing stressors to increase risks for child emotional and behavioral problems. Using a CBPR approach, a family based prevention model, the Family Strengthening Intervention for Refugees (FSI-R) was adapted from a tested model used in Africa and designed for delivery by refugee community health workers with through a process involving stakeholder consultation and local refugee Community Advisory Board input. Pilot data on the FSI-R demonstrates strong feasibility and acceptability, but further data are needed on effectiveness as well as barriers and facilitators to implementation by community health workers embedded in refugee-serving social services agencies. Specific aims are to (1) examine the impact of a family-based preventive intervention on outcomes of parent-child relationships, family functioning, and child mental health using a Hybrid Type 2Effectiveness-Implementation Design (families with children aged 7-17 in a two-arm randomized controlled trial); (2) identify barriers and facilitators to implementation of the FSI-R by community health workers by conducting a process evaluation concurrent with the delivery of the intervention; and (3) strengthen the science of community engagement to address health disparities by fortifying CBPR-based pathways of change via collaborative partnerships between refugee communities, service providers, and academic stakeholders.